Boca Raton-based Vitacost sells more than 45,000 healthy living products, including vitamins, supplements and personal care items to about 2.3 million active customers.

Kroger plans to buy Vitacost's outstanding shares at $8 per share in cash, about $280 million. The purchase price represents a premium of 51 percent to Vitacost's closing share price on Feb. 19, the day before a major Vitacost shareholder publicly requested that the company evaluate strategic alternatives, Kroger said in a statement.

The transaction is expected to close in the third quarter of the year.

The acquisition will help Kroger serve customers through ship-to-home orders in all 50 states, including 16 states where Kroger doesn't have stores, the Cincinnati-based retailer said.

Vitacost reported $382.7 million in net sales in 2013, up 15.7 percent from 2012.

Once the deal is complete, the South Florida company will operate as a subsidiary of The Kroger Co. and keep its offices in Boca Raton, its distribution facilities in North Carolina and Nevada and customer service center in North Carolina.